Telephone-relay.



E. F. w. ALBXANDBRSON.

TELEPHONE RELAY.

APPLICATION FILED JN.'2,5, 1908 902,195'. Patented 0m21.190s.

L y I UNITED STATES PATENT opinion,.-

ERNST new. ALEXANDERsoN,-"0F 'sCnENECTADx NEW YORK, 4AssieNoR To GENERAL ELECTRIC CoiirANinA CORPORATION QRNEW YORK.

,TELEPHONE-RELAY.

Specification of Letters Patent.

'Patented oct. 27, 190s.

Application led January 25, l1908.A Serial No, 412,555. I

To al'who/m, 'it may concern):

Beit known that I, ERNST F. AW. ALEX'- `ANDERSON, a citizen of the United States, re-

Telephone-Relays, of which the followingis a' specification.

` '-My invention relates to telephone relays,

and'V its object is to provide a'telephonere-v lay of novel design, which is of practical and-commercial. value. l Itlias been proposed heretofore to employ as telephone relays dynamo-electric ma` Chines of the direct-current type, havin lthe i'ield winding inthe primary circuit an the part bein armature winding in. the secondary circuit,

so as to produce in tlie'secondary circuit cu'r-y rentsC of the -same frequency' and Wave-form as the currents in the primarycircuit. The operation of such 'devices is interfered with by the disturbing effect ofthe collectingdevices, and, so far as I am aware, no relay of this type is in. commercial use. f

My Invention, broadly stated, consists in using al dynamoelectric machine of the high-frequencyinductor-alternator type as a telephone relay. In such`a machine both the field winding and the armaturewinding may be stationary; the only moving by 'the fie d winding. I design the inductor `so that its natural frequency, which is de' `termined by the number of its poles and its speed, is very high compared with the frequencylof the currents in a telephone circuit, so that each wave or pulsation of the telephone current corresponds to a-,large *number ofthe alternations due to the movement of the inductor. The variation of the current in the primarycircuitin which the f field winding is connected does not change thefrequency ofthe armature currents but does change the amplitude of these currents; andif their frequency is above that of an audible note, the effect on a telephone receiver is simply that of the variation in am-` plitude, which corresponds to the variation of current in the rimary circuit. My invention A'novel features in the constructionof the in- 1 ductijona ternator, whereby its eficiency is improve vthe inductor, which is magnetizedurther comprises certainv Thse frames', which Win be definitely.

best be understoodby reference to the accompanying drawing,fin which Figure l shows a partial end view partly in cross-section, of an ,inductor alternator designed in accordance with my invention for use in a telephonerelay; Fig. 2 shows a side elevation ofl the same;l Fig. 3 shows a. detail perspective view; Fig. 4 1s a diagram of connections; and Fig. 5 is adiagramof thecur'rent waves in the machine.

vInfthe drawing, A A represent end-frames. or standards between which .the magnetie circuit of the stator is secured. This magnetic circuit comprises bundles or blocks of 'laminatio'ns B B, arrangediadially and surrounding the eld coil C,` which extends vcircumferentially around-l the machine, and

the lami'nations D, which extend in. av circumferential direction, landform with the laminations B a nearlyclosed magnetic circuit for the fieldl winding C.v The laminations are supported and spaced apart 'by non-magnetic spacing blocks E. The airgap in the magnetic circuit ofthe stator has its opposite faces lyin in. adjacent radial planes; and in slots on t ese facesfare placed the coils F of the armature winding.

G represents the inductor, which is shaped or maximum strength with respect to cen-l trifugal strains, in order that it may be -op'-4 erated at very high speeds. lThis Aindnctor carries at its rim magnetic poles H formed yof small bundles of laminations, which revolve between the opposite faces of the mag' netic circuit of the stator. Non-magnettc blocks I may be placed between the magnetic poles H, in order to strengthen the poles mechanically, andto decrease windage losses.'

The connections of the field and armature windings are as indicated in Fi 4. The

' field winding C Dis^connected in circuit with a source of current J and Atelephone transmitter K, either directly or through a trans`v former, accordingto common telephone, practice. The armature winding F is -connected in circuit with a suitable receiving device, which may comprise Ca liquid receiver M of a type well known in wireless telegrapliy,and a telephone receiver L and a source of current N connected in shunt to the liquid receiver M`; the principle of ,this arrangement being that the high-frequency alternations impressed on the liquid receiver. M vary its resistance, and the resistance variations result in current variations in the,

KGO

telephone receiver, which are vaudible therein. 4It Will b e understood that the particular form of receiving device is no part of my invention, and any suitable form of receiver may be employed." The principle of operation of the telephone relay is as follows: rlhe currents in the armature or transmitter circuit vary in' amount'when a message is being., transmitted, and this variation ,may be represented bythe curve o in F ig. 5. f The currents induced in the armature Windingy are of a high frequency, compared with the currents in the primary circuit, and may be represented by the curve j' in Fig. 5. The fre-l quency of these currents is not affected by the `currents in the primary circuit, but their amplitude is affected and varies in pro-L portion to the primary curjrent, as is shown in 5. lI`he frequency of thel armature currents ispso high as tp be inaudible in ay telephone receiver, but the variationin amplitude produces audible sounds 1n the receiver of similar quality to, but of greater amount than, those that would be heard if a telephone receiver Were substituted for the field winding of the alternatorin the primary circuit.. l' t It has already been pointed out that the stator' laminations 'D extend circumferentially, While the laminations B, forming the .greater part of the magnetic circuit, extend radially. The purpose of the ciroiunferen- 'due to the currents in these coils can close v i ducing-'any Variations in duetor alternator having both-field and artial arrangement of the laminations D is to iocalize the ux variations due to the highfrequencyn armature currents. Since the laminatmns 1n which the armature coils are xplaced extend circumferentially., the flux itselfd-irectly aroun \-the coils, Without protthe' marn part of the magnetic circuit. y v

i/V'hat I claim as new and :desire to secure by. k@Setters Patentof-the UnitedfState's, is:

1."A ,telephone relay comprisinlga highfrequency inductor alternator having a stationary'eld Winding connected in the primary circuit and a 'stationary armature Winding connected in the secondary circuit.

'2'. In combination, a high-frequency inmature windings4 stationary, a telephonel transmitter and a source of current in circuit with the-field winding -of the alternator, and 55 a telephone receiver in circuit With the armature Winding of the alternator.

`3. A telephone relaymcomprising a laminated stator, a-stationary field Winding connected 1n the, primary circuit, an inductor magnetized therebyadapted to be driven at I high speed and having a large number of laminated polarprojections, anda stationary armature windmg connected 1n the secondary circuit and adapted to have high frequency` alternating-current induced in it by said inductor. 'I 4. i' telephone relay comprising a laminatetf stator having oppositefaces lying in adjacent radial planes, a stationary held winding connected in the primary circuit, an inductor magnetized thereby adapted to be driven at high speed and having a large number of laminated polar projections extending between the opposite stator faces, and a winding carried in slots onsaid faces and connected in the secondary circuit.

5, A telephone relay comprising a laminated stator' having opposite faces lying in adjacent radial planes,'the laminations near said faces extending circumferentially, a stationary field Winding connected in the primary circuit, an inductor magnetized thereby adapted to be driven at high speed and having a large number of narrow laminated polar projections extending between the opposite faces, and a, Winding carried `in slots on said faces and connected y,in the secondary circuit.

6. A telephone relay comprising a lami- Nnated stator having opposite faces lying in adj acent radial planes, the laminations forming the greater part of the magnetic circuit lymg 1n substantially radial planes, but the laminations near said faces -extending circumferentially, a stationary field Winding connected in the primary circuit, an inductor magnetized thereby adapted to be driven lat high speed and having a large number of Anarrow laminated, polar projections extendinductor magnetized therebyl adapted'to be' driven at high speed and having la large number of laminated polar. projections extending between the opposite stator faces, the spaces rbetween lsaid polar projections being illed with non-magneticv material, and a Winding carried 1n slots on said faces kand connected in the secondary circuit.

In Witnesswhereof, I have hereunto set my hand this 23rd day-of January, 1908.

i ERNST F. W. ALEXANDERSON. Vitnesses:

BENJAMIN l B. HULL,

HELEN ORFoRD. 

